Face Masks of Questionable Value Against SARS

Experts don't think respiratory illness is spread through casual contact

FRIDAY, April 4, 2003 (HealthDayNews) -- From Asia to North America, frightened citizens and airplane passengers are slipping on face masks to protect themselves against the deadly respiratory illness known as SARS.

But experts say they may be wasting their money.

Some are buying the wrong kind of masks -- the surgical kind won't do -- or don't know how to use the right kind correctly.

"The masks I see in pictures in newspapers don't fit very well, and if they don't, they're absolutely useless," said James Vincent, chairman of the department of environmental health sciences at the University of Michigan.

To make matters more complicated, researchers still aren't sure how SARS -- severe acute respiratory syndrome -- is transmitted, and no masks are 100 percent effective against airborne germs.

In Hong Kong, the illness spread rapidly to more than 240 people in one apartment complex, casting doubt on the belief that it is only transmitted through close personal contact or respiratory drops from coughing or sneezing.

As of Sunday, there have been at least 89 deaths, with more than 2,300 people infected in 18 countries in Asia, Europe and North America. The United States has an estimated 100 suspected cases in 28 states.

But many experts remain confident that SARS is not easily transmitted through casual contact.

"If everybody wore masks, it would be overkill," said Dr. Carl R. Chudnofsky, chairman of the department of emergency medicine at Albert Einstein Medical Center in Philadelphia. "Casual contact from walking down the street or being in a store is not enough to get the disease."

Sales of face masks are booming amid worldwide concern, and some international airlines have begun handing out masks to passengers alongside headsets and blankets. The 3M company, which produces a common type of respiratory or dust mask known as N-95, has reportedly put its factories to work 24 hours a day to meet demand.

The N-95 mask, which resembles a surgical mask, includes a filter that keeps out 95 percent of particles that are 0.3 microns across or larger. Other types of masks keep a higher percentage of particles at bay, but they are less common.

But surgical masks, commonly used by doctors performing operations, won't do much to prevent infection in wearers.

"They're designed to prevent the exit of germs from the body," said Dr. Don Milton, a lecturer on environmental health at the Harvard School of Public Health. "A surgeon does not want to contaminate a wound with his or her own bacteria and viruses, which may be totally harmless in the surgeon's mouth but very bad for the patient's open tissues."

Even so, Milton added, those infected with SARS should wear surgical masks to avoid infecting people around them, such as family members and hospital personnel. The U.S. Centers for Disease Control and Prevention (CDC) agrees.

U.S. health officials are also calling upon hospital workers to wear disposable N-95 masks when they treat patients who may have SARS. The masks, which typically come in light blue and pink, cover much of the face.

But putting them on isn't as simple as it looks, experts said.

The CDC recommends that users undergo "fit testing" to make sure the masks fit tightly against the face. Children and men with beards may not find any masks that fit.

"If there's a gap that you can put your finger in, most of what you're inhaling will come through," Vincent said. "The air takes the path of least resistance."

To make matters worse, it's hard to breathe through a mask, and it can become hot and uncomfortable. "At the end of the day, you're dying to take the thing off," Vincent said.

Barbara Muzzarelli, a registered nurse and infection control expert in El Centro, Calif., said you shouldn't treat a mask as the only possible protection from germs.

"It wouldn't hurt to put a mask on, but you've got to remember to wash your hands," she said. "You can't just do one without the other."

Scientists seeking the cause of SARS suspect it may be a virus similar to the cold virus and therefore transmitted through saliva and mucus. Handshakes and doorknobs could conceivably spread the disease.

At a CDC news conference Friday, Dr. James Hughes, director of the National Center for Infectious Diseases, reinforced that belief.

"The experience with this disease still suggests that the bulk of transmission occurs by droplets, which occur from close contact of three to six feet," Hughes said. "But, there are some features that remind us to keep an open mind, such as the role that inanimate objects might play. Those are the reasons we have emphasized good personal hygiene."

"In the U.S.," he added, "if you haven't traveled to an affected area or if you haven't been exposed to an ill person, you're not at [high] risk. The importance of personal hygiene, and as with many infections and certainly this one, the importance of hand hygiene and appropriate hand washing can't be overemphasized. We would like to remind everybody that if they have a respiratory infection even if unrelated to this, it is appropriate not to cough and sneeze on other people."

Muzzarelli added that a healthy lifestyles -- plenty of sleep, physical fitness and a good diet -- may be the best defense against illnesses like SARS. With no treatment available yet, the human body is on its own.

"It's your immune system, your ability to fight disease, and you've got to help it out," she said.

More information

Learn about the CDC's recommendations on face masks and SARS by clicking here. You can also get updates on SARS from the World Health Organization.

SOURCES: James Vincent, Ph.D., D.Sc., chairman, department of environmental health sciences, University of Michigan School of Public Health, Ann Arbor; Don Milton, M.D., Dr.P.H., lecturer on Occupational and Environmental Health, Harvard School of Public Health, Boston; Barbara Muzzarelli, R.N., CIC, infection control practitioner, El Centro Regional Medical Center, El Centro, Calif.; Carl R. Chudnofsky, M.D., FACEP, chairman, department of emergency medicine, Albert Einstein Medical Center, Philadelphia; James Hughes, M.D., director, National Center for Infectious Diseases, Atlanta
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